Metal battery cell and preparation method therefor, battery device, and electric device

Abstract

The present application relates to the technical field of batteries, and in particular to a metal battery cell and a preparation method therefor, a battery device, and an electric device. The metal battery cell comprises a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte solution, wherein the negative electrode sheet comprises a negative electrode current collector and a gel polymer layer stacked on at least one surface of the negative electrode current collector, and the gel polymer layer has a hollow structure. In the metal battery cell in embodiments of the present application, on the basis of the special gel polymer layer formed on the negative electrode sheet, the safety performance of the battery is further improved on the basis that the battery has good initial efficiency performance.

Description

Metal battery cell, preparation method thereof, battery device and electric device

[0001] The present application claims priority to the Chinese patent application No. 202411343572.X, filed on September 25, 2024 in the China Patent Office and entitled "Metal battery cell, preparation method thereof, battery device and electric device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application belongs to the technical field of battery, in particular relates to a metal battery cell, a preparation method thereof, a battery device and an electric device. BACKGROUND

[0003] With the vigorous development of new energy vehicles, the battery driving system becomes an important factor affecting the performance and cost of new energy vehicles, and the secondary battery becomes the first choice of power supply in the battery driving system due to its high energy density, low memory effect and high working voltage.

[0004] The secondary battery generally includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte. For metal batteries that do not use carbon / silicon and other intercalation type negative electrode active materials, the locking liquid capacity of the negative electrode sheet is poor, and the electrolyte is easy to accumulate at the bottom of the battery under the action of gravity, resulting in less electrolyte at the top of the battery, and metal deposition is easy to occur on the negative electrode current collector, which in turn promotes dendrite growth. If the reserved space is insufficient, dendrite growth is easy to pierce the separator and cause short circuit. SUMMARY

[0005] The purpose of the present application is to provide a metal battery cell, a preparation method thereof, a battery device and an electric device, aiming at the technical problem of how to improve the safety performance of the metal battery.

[0006] To achieve the above-mentioned application purpose, the technical scheme adopted by the present application is as follows:

[0007] In a first aspect, the present application provides a metal battery cell, comprising a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte; wherein the negative electrode sheet comprises a negative electrode current collector and a gel polymer layer stacked with at least one surface of the negative electrode current collector, and the gel polymer layer has a hollow structure.

[0008] The gel polymer layer with a hollow structure is stacked on the surface of the negative current collector of the metal battery cell. The gel state of the gel polymer has good wettability to the electrolyte. After the gel polymer and the electrolyte are in contact, the electrolyte can be locked well, and the electrolyte is not easy to separate during battery storage. At the same time, the space structure of the hollow structure of the gel polymer layer can reserve a certain gap space, which is beneficial to alleviate the risk of the negative electrode sheet surface dendrite growing to pierce the isolation film during the cycle process, thereby improving the safety performance of the battery. Therefore, the metal battery cell based on the gel polymer layer with the special structure of the negative electrode sheet can further improve the safety performance of the battery on the basis of good initial efficiency of the battery.

[0009] In some embodiments, the hollow structure of the gel polymer layer includes at least one of a network structure, a linear structure, and an island structure.

[0010] The gel polymer layer with different shapes described above not only provides a certain buffer space for metal deposition on the surface of the negative electrode sheet to better reduce the risk of dendrite piercing the isolation film, but also improves the flexibility of the negative electrode sheet as a whole when the gel polymer layer is combined on the surface of the negative current collector, which is more conducive to the assembly of the battery.

[0011] In some embodiments, the gel polymer layer has a network structure, and the network hole size in the network structure is 1-10 mm; or,

[0012] The gel polymer layer has a linear structure, and the distance between adjacent lines in the linear structure is 1-10 mm.

[0013] The network or linear gel polymer layer with the above size can provide sufficient space for metal deposition on the surface of the negative electrode sheet.

[0014] In some embodiments, the thickness of the gel polymer layer is 5-150 μm;

[0015] And / or, the gel polymer area on the surface of the negative current collector accounts for 5-40% of the total area of the gel polymer layer.

[0016] The gel polymer layer with the above thickness can provide sufficient space between the positive electrode sheet and the negative electrode sheet to alleviate the risk of dendrite piercing the isolation film, and has strong liquid retention capacity for the electrolyte. The gel polymer layer formed by the above gel polymer area has good liquid retention capacity for the electrolyte, and can provide sufficient metal deposition space, significantly reduce the dendrite deposition thickness, and better reduce the risk of dendrite piercing the isolation film.

[0017] In some embodiments, the gel polymer comprises at least one of a polymethyl methacrylate-based gel polymer, a polyethylene oxide-based gel polymer, a polyacrylonitrile-based gel polymer, and a polyvinylidene fluoride-based gel polymer.

[0018] The gel polymer of the above kind is used in the negative electrode tab, which can well improve the safety performance of the battery.

[0019] In some embodiments, an electrically conductive coating is arranged between the negative current collector and the gel polymer layer.

[0020] By adding the electrically conductive coating between the negative current collector and the gel polymer layer, the overall electrically conductive performance of the negative electrode tab can be improved.

[0021] In some embodiments, the electrically conductive coating comprises an electrically conductive carbon layer; and / or,

[0022] The thickness of the electrically conductive coating is 2-20 μm.

[0023] The above electrically conductive coating can make the electrically conductive performance of the negative electrode tab better.

[0024] In a second aspect, the embodiments of the present application provide a preparation method of a metal battery cell, comprising:

[0025] Preparation of a polymer slurry;

[0026] Printing the polymer slurry on at least one surface of the negative current collector by using a 3D printing process to form a polymer layer with a hollow structure, to obtain a negative electrode tab;

[0027] After assembling the negative electrode tab, a positive electrode tab, and a separator into an electrode assembly, injecting an electrolyte to form a gel polymer layer on the polymer layer, to obtain a metal battery cell.

[0028] By using the 3D printing technology, the morphology and spacing of the printing material are accurately controlled, so that the gel polymer layer with a hollow structure is formed on the negative current collector. On the one hand, the gel polymer of the gel polymer layer has good liquid absorption and liquid retention capacity for the electrolyte. On the other hand, the hollow structure of the gel polymer layer can provide a certain gap space, which can well provide space for the growth of negative electrode dendrites. Therefore, the metal battery cell prepared by the embodiments of the present application has a gel polymer layer based on the unique structure of the negative electrode tab, which can further improve the safety performance of the battery on the basis of good initial efficiency performance of the battery.

[0029] In some embodiments, the hollow structure of the polymer layer comprises at least one of a network structure, a linear structure, and an island structure.

[0030] By printing the polymer layer of different shape structure, the subsequent contact with the electrolyte forms a gel polymer layer of corresponding shape structure, so that the obtained metal battery monomer not only provides a certain buffer space for the metal deposition on the surface of the negative electrode sheet, but also improves the flexibility of the negative electrode sheet as a whole, which is more conducive to the assembly of the battery.

[0031] In some embodiments, the polymer slurry comprises: a polymer, a polymerizable monomer, and a photoinitiator, and the polymerizable monomer is a monomer corresponding to the polymer.

[0032] In the polymer slurry, the polymerizable monomer and the photoinitiator are added on the basis of the polymer, so that part of the polymer can be synthesized in situ during the printing process, further improving the overall uniformity and structure controllability of the polymer layer.

[0033] In some embodiments, the polymer comprises at least one of polymethyl methacrylate-based polymer, polyethylene oxide-based polymer, polyacrylonitrile-based polymer, and polyvinylidene fluoride-based polymer.

[0034] The gel polymer layer formed by the above-mentioned polymer can well improve the safety performance of the battery.

[0035] In some embodiments, the mass ratio of the polymer to the polymerizable monomer is (4:6) to (2:8);

[0036] And / or, the photoinitiator accounts for 4-8% of the total mass of the polymer and the polymerizable monomer.

[0037] The above-mentioned mass ratio of the polymer slurry can well form a polymer layer in situ.

[0038] In some embodiments, the viscosity of the polymer slurry at 25°C is 1500-2000 cps;

[0039] The temperature condition for printing the polymer slurry is 60-80°C.

[0040] The polymer slurry with the above-mentioned viscosity is not easy to block, improving the printing efficiency. And the above-mentioned temperature can well make the polymer slurry form a polymer layer.

[0041] In some embodiments, the conditions of the 3D printing process comprise:

[0042] (1) the printing speed is 150-200 mm / min;

[0043] (2) the light wavelength is 360-370 nm;

[0044] (3) the light intensity is 200-240 mW / cm2 ;

[0045] (4) The light irradiation time is set to 60-100 s.

[0046] The printing process parameters can make the polymer slurry form a polymer layer with a hollow structure.

[0047] In a third aspect, the embodiments of the present application provide a battery device, which comprises the metal battery monomer provided in the first aspect of the embodiments of the present application or the metal battery monomer prepared by the preparation method provided in the second aspect of the embodiments of the present application.

[0048] The battery device has good safety performance and can work better by using the metal battery monomer provided in the embodiments of the present application.

[0049] In a fourth aspect, the embodiments of the present application provide an electric device, which comprises the metal battery monomer provided in the first aspect of the embodiments of the present application, the metal battery monomer prepared by the preparation method provided in the second aspect of the embodiments of the present application or the battery device provided in the third aspect of the embodiments of the present application.

[0050] The electric device has a long service life and can work better by using the metal battery monomer or the battery device provided in the embodiments of the present application.

[0051] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0052] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Moreover, the same reference numerals in the various drawings indicate the same or similar elements. In the drawings:

[0053] FIG. 1 is a schematic structural diagram of a battery monomer of an embodiment of the battery of the present application;

[0054] FIG. 2 is an exploded schematic diagram of the battery monomer shown in FIG. 1;

[0055] FIG. 3 is a schematic structural diagram of an embodiment of a battery module of the present application;

[0056] FIG. 4 is a schematic structural diagram of an embodiment of a battery pack of the present application;

[0057] FIG. 5 is an exploded schematic structural diagram of the battery pack shown in FIG. 4;

[0058] FIG. 6 is a schematic diagram of an embodiment of a power consuming device including the battery of the present application as a power source;

[0059] FIG. 7 is a schematic diagram of a structure of a gel polymer forming a networked polymer layer in the battery of the present application.

[0060] Reference Signs List: 10 - battery cell; 11 - case; 12 - top cover assembly; 13 - electrode assembly; 20 - battery module; 30 - battery pack; 31 - upper case; 32 - lower case. DETAILED DESCRIPTION

[0061] The embodiments of the present application will be described in detail with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore should not be used to limit the protection scope of the present application.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the present specification and claims can be referred to in connection with the above description of drawings and terms of the specification and claims, the terms "include" and "have" and any variations thereof, are intended to cover the non-exclusive inclusion.

[0063] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0064] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0065] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents a "or" relationship between the front and rear associated objects.

[0066] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces). "At least one" refers to one or more (including one, two, three, etc.).

[0067] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0068] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0069] With the increasing depletion of traditional energy resources, the development of new energy storage devices is increasingly valued. Among them, secondary batteries are of great concern due to their high energy density, high theoretical capacity, good cycle stability and environmental protection characteristics. Secondary batteries can not only be applied to energy storage power systems such as hydroelectric, thermal, wind and solar power stations, but also be widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles. With the continuous expansion of the application field of secondary batteries as power batteries, the market demand is also increasing.

[0070] Rechargeable battery, also known as secondary battery, refers to a battery that can be activated by charging after discharging. Among them, the battery using liquid electrolyte is also called liquid battery. The metal battery in it is a battery in which no carbon / silicon or other intercalation type negative active material is used in the negative electrode sheet, and active metal is formed on the surface of the negative electrode sheet after cycling. For example, lithium metal battery, sodium metal battery, etc. Because the negative electrode sheet does not use carbon / silicon or other intercalation type negative active material, metal deposition occurs on the negative electrode current collector, which promotes dendrite growth. If there is not enough space reserved, dendrite growth can easily pierce the separator film and cause short circuit, resulting in battery failure. Moreover, the negative electrode sheet of the metal battery has low liquid retention capacity, and the electrolyte is easily accumulated at the bottom of the battery under the action of gravity, resulting in stratification and bridge breaking of the electrolyte at the top of the battery during the cycling process, thereby causing the cycle to dive.

[0071] Based on this, the gel polymer layer with a hollow structure is printed on the surface of the negative current collector of the metal battery cell by using the 3D printing process in the embodiments of the present application. By using the good wettability and liquid retention capacity of the gel polymer to the electrolyte, and the space structure of the gel polymer layer to prevent the risk of dendrite piercing, the performance of the battery can be improved. The specific technical solutions are as follows.

[0072]

Metal battery cell and preparation method thereof

[0073] In a second aspect, the embodiments of the present application provide a metal battery cell. Specifically, it includes: (1) a positive electrode sheet, which includes a positive electrode current collector and a positive electrode active layer arranged on at least one surface of the positive electrode current collector, i.e. the positive electrode active layer is arranged on one surface of the positive electrode current collector or both opposite surfaces are provided with the positive electrode active layer. (2) a negative electrode sheet, which is arranged opposite to the positive electrode sheet, and includes a negative electrode current collector and a gel polymer layer laminated with at least one surface of the negative electrode current collector, i.e. the gel polymer layer is arranged on one surface of the negative electrode current collector or both opposite surfaces are provided with the gel polymer, and the gel polymer layer has a hollow structure. (3) a separator film, which is located between the positive electrode sheet and the negative electrode sheet, mainly plays the role of preventing the short circuit of the positive and negative electrodes, and can also make the active ions pass through. (4) electrolyte, which is a solution containing electrolyte, and the electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet.

[0074] Gel polymer, also known as polymer gel, is a three-dimensional network or interpenetrating network formed by cross-linking polymerization of molecular chains and a solvent to form a system containing liquid and solid. Lattice / Perforated: refers to the lattice-like, line-like holes or gaps formed in the internal or spatial structure of the gel polymer layer. The lattice structure usually has a repeating geometric shape, which can be square, circular, diamond, etc. Based on the spatial network structure of the lattice gel polymer layer, it has good wettability and liquid retention capacity for electrolyte; at the same time, the gel polymer layer can provide a buffer space for the growth of negative dendrite.

[0075] The lattice gel polymer layer can be understood as a gel polymer layer formed by a plurality of polymer-free material regions. On the one hand, the gel polymer of the gel polymer layer has good liquid absorption capacity for electrolyte, and on the other hand, the three-dimensional lattice structure of the gel polymer layer can provide a certain gap space, which can provide space for the growth of negative dendrite. Therefore, the metal battery cell prepared by the embodiments of the present application has a unique gel polymer layer formed based on the negative electrode sheet, which not only helps to exert the capacity and make the battery have good initial efficiency, but also helps to improve the safety performance of the battery. The safety performance is mainly reflected in the improvement of the cycle life and the storage life.

[0076] In the embodiments of the present application, the gel polymer used in the negative electrode sheet can be identified by methods such as infrared spectroscopy or Raman spectroscopy and nuclear magnetic resonance determination of corresponding functional groups.

[0077] In the embodiments of the present application, the wetting capacity of the gel polymer can be characterized by contact test with the system electrolyte. The contact angle refers to the tangent line of the gas-liquid interface made at the three-phase intersection of gas, liquid and solid, and the included angle between the tangent line on the liquid side and the solid-liquid boundary line. The contact angle measuring instrument uses the principle of optical imaging; through manual or automatic liquid dropping, the volume of each drop is ensured to be the same, high-resolution cameras ensure optical stability, and test results are analyzed in real time by measurement software. The results show that the contact angle between the gel polymer and the electrolyte after the gel polymer is coated on the surface of the negative electrode sheet is significantly reduced.

[0078] In the embodiments of the present application, the liquid retention capacity of the gel polymer can be tested by coating the gel polymer on the surface of the negative current collector, then cutting it into a square, weighing the initial weight of the square with a millionth electronic balance and recording it. The two current collectors coated with and without gel polymer are soaked in electrolyte for a period of time, the weight of the soaked electrode sheet is weighed, the electrolyte adsorption capacity of different electrode sheets is calculated, and the size of the electrolyte adsorption capacity is used to characterize the strength of the electrolyte liquid retention capacity. The results show that the electrolyte adsorption capacity of the gel polymer on the surface of the negative current collector is significantly increased.

[0079] In some embodiments, the hollow structure of the gel polymer layer includes at least one of a mesh structure, a linear structure, and an island structure. The polymer layer with different shapes described above not only provides a certain buffer space for metal deposition on the surface of the negative electrode tab to better reduce the risk of dendrite piercing the separator, but also improves the flexibility of the negative electrode tab when the polymer layer is combined on the surface of the negative electrode current collector, which is more conducive to the assembly of the battery when the positive electrode tab, the separator, and the negative electrode tab are assembled into a battery.

[0080] In some embodiments, the gel polymer layer has a mesh structure, and the mesh structure has a mesh size of 1-10 mm; that is, the gel polymer forms a plurality of strips, and the strips are longitudinally and transversely interlaced to form a mesh with a mesh size of 1-10 mm. Alternatively, the gel polymer layer has a linear structure, and the linear structure has a spacing between adjacent lines of 1-10 mm; that is, the gel polymer forms a plurality of parallel lines, and the spacing between adjacent lines is 1-10 mm. The gel polymer layer with the mesh structure or the linear structure described above can provide sufficient space for metal deposition on the surface of the negative electrode tab, thereby reducing the risk of dendrite piercing the separator.

[0081] In some embodiments, the gel polymer includes at least one of a polymethyl methacrylate (PMMA) based gel polymer, a polyethylene oxide (PEO) based gel polymer, a polyacrylonitrile (PAN) based gel polymer, and a polyvinylidene fluoride (PVDF) based gel polymer. The use of the gel polymer of the above types in the negative electrode tab can well improve the cycle life and storage life of the battery.

[0082] After the gel polymer layer with a hollow structure is provided in the negative electrode tab, the electrolyte solvent contacts the gel polymer layer, and a gel-like ion channel is formed between the negative electrode tab and the separator layer, so that the ions can pass through quickly, while the gel polymer layer formed by the gel polymer has good mechanical stability and isolation performance, and the electrolyte is locked in the gel polymer layer. When the battery is stored for a long time, the electrolyte is less likely to penetrate into the bottom of the battery, and the risk of cycle diving of the battery during charging and discharging is significantly reduced. At the same time, the gel polymer layer with the hollow structure described above can provide sufficient space for metal deposition on the surface of the negative electrode tab, thereby reducing the risk of dendrite piercing the separator.

[0083] Among them, it can be used for methyl methacrylate based gel polymer, polyethylene oxide based gel polymer; It has good compatibility in the system, and the corresponding battery immersion verification proves that the gas production and discoloration reaction is less.

[0084] In some embodiments, the thickness of the gel polymer layer contained in the negative electrode tab is 5-150 μm; for example, the thickness of the gel polymer layer can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 130 μm, 140 μm, 150 μm, or the like. The gel polymer layer with the above thickness can provide sufficient space between the positive electrode tab and the negative electrode tab to mitigate the risk of dendrite piercing the separator, while having strong liquid retention capability for the electrolyte.

[0085] In some embodiments, the percentage of the gel polymer area on the surface of the negative current collector to the total area of the gel polymer layer is 5-40%. The gel polymer layer has a reticular, linear, or island shape, wherein the area of the gel polymer on the surface of the negative current collector is the actual space area occupied by the gel polymer, and the area of the gel polymer layer on the surface of the negative current collector can be understood as the printing area on the surface of the negative current collector. Since there are multiple areas without polymer materials in the gel polymer layer, the area of the gel polymer is smaller than the total area of the gel polymer layer; the gel polymer occupies 5-40% of the total area of the gel polymer layer, and the remaining area is the area without polymer materials in the gel polymer layer. For example, the percentage of the gel polymer area to the total area of the gel polymer layer can be 5%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 28%, 30%, 32%, 35%, 40%, or the like. Within this range, the gel polymer layer not only has good liquid retention capability for the electrolyte, but also has good ion transmission channels, and provides sufficient space for metal deposition on the surface of the negative electrode tab.

[0086] In some embodiments, the gel polymer layer is formed by a 3D printing process. Specifically, a UV printer (Ultraviolet LED Inkjet Printer) can be used for printing. For example, for an inorganic sodium metal battery, the polymer slurry is printed on the negative flat plate electrode by a 3D printing process, and then the electrode is assembled into a battery cell and liquid injected to form a gel polymer layer, thereby obtaining a metal battery monomer.

[0087] In some embodiments, the negative current collector can be a metal foil or a composite current collector. For example, as a metal foil, an aluminum foil or a copper foil can be used. Metal deposition is prone to occur on the negative current collector of the metal battery monomer, and since the metal has high reactivity, dendrite growth is prone to occur, and the liquid retention capability for the electrolyte is lower. The gel polymer layer with the hollow structure based on the embodiments of the present application can effectively reduce the risk of dendrite piercing the surface of the negative electrode tab.

[0088] In some embodiments, a conductive coating is arranged between the negative current collector and the gel polymer layer. By adding a conductive coating on the surface of the negative current collector of the metal battery monomer, the conductivity of the negative electrode tab of the battery can be further improved.

[0089] In some embodiments, the conductive coating layer includes a conductive carbon layer; the conductive carbon has good conductivity. The thickness of the conductive coating layer is 2-20 μm, and can be 2 μm, 4 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, etc. The conductive coating layer can better improve the conductivity of the negative electrode sheet.

[0090] The preparation method of the metal battery cell provided in the embodiments of the present application includes assembling the positive electrode sheet, the negative electrode sheet, the separator and the electrolyte into a battery.

[0091] In some embodiments, the step of preparing the positive electrode sheet includes preparing a positive electrode slurry containing a positive electrode active material, and then coating the positive electrode active material on at least one surface of the positive electrode current collector to form a positive electrode active layer.

[0092] In some embodiments, the step of preparing the negative electrode sheet includes coating a conductive coating layer on at least one surface of the negative electrode current collector, and then printing a polymer slurry on the surface of the conductive coating layer by using a 3D printing technology to form a polymer layer with a hollow structure. Then, the prepared negative electrode sheet, the positive electrode sheet and the separator are assembled with the electrolyte to obtain a battery cell. For example, the prepared positive electrode sheet, the separator and the negative electrode sheet are stacked in order, with the separator between the positive electrode sheet and the negative electrode sheet to play a separating role, and then wound to obtain an electrode assembly; the electrode assembly is placed in a battery case, dried, and then injected with the electrolyte, and then subjected to formation and standing processes to obtain the metal battery cell.

[0093] In some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode active layer disposed on at least one surface of the positive electrode current collector, and the positive electrode active layer contains a positive electrode active material. For example, in a lithium metal battery cell, the positive electrode active material is a lithium-containing material, and for example, in a sodium metal battery cell, the positive electrode active material is a sodium-containing material. As an example, the positive electrode active material of the lithium metal battery cell can include at least one of the following materials: lithium-containing phosphate with an olivine structure, lithium transition metal oxide and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone or in combination with two or more. Among them, the positive electrode active material containing a transition metal element can be a lithium transition metal oxide, and examples of the lithium transition metal oxide can include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2(also can be referred to as NCM 333 O2(also can be referred to as NCM 0.5 O2(also can be referred to as NCM 0.2 O2(also can be referred to as NCM 0.3 O2(also can be referred to as NCM 523 O2(also can be referred to as NCM 0.5 O2(also can be referred to as NCM 0.25 O2(also can be referred to as NCM 0.25 O2(also can be referred to as NCM 211 O2(also can be referred to as NCM 0.6 O2(also can be referred to as NCM 0.2 O2(also can be referred to as NCM 0.2 O2(also can be referred to as NCM 622 O2(also can be referred to as NCM 0.8 O2(also can be referred to as NCM 0.1 O2(also can be referred to as NCM 0.1 O2(also can be referred to as NCM 811 O2(also can be referred to as NCM 0.85 O2(also can be referred to as NCM 0.15 O2(also can be referred to as NCM 0.05 O2(also can be referred to as NCM

[0094] For the electrolyte, when it is a lithium metal battery cell, the corresponding electrolyte is a lithium salt, which can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorobisoxalateborate, lithium bisoxalateborate, lithium difluorobisoxalatephosphate, and lithium tetrafluorobisoxalatephosphate. When the battery is a sodium metal battery cell, the electrolyte can be obtained by replacing the lithium ion in the above electrolyte salt with a sodium ion.

[0095] In some embodiments, the positive current collector of the positive electrode tab can be a metal foil or a composite current collector. For example, as the metal foil, an aluminum foil can be used. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.

[0096] In some embodiments, the positive active layer of the positive electrode tab can also optionally include a binder. The binder can be selected from at least one of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). The positive active layer can also optionally include a conductive agent. The conductive agent can be selected from at least one of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the positive active layer can also optionally include other auxiliary agents, such as dispersants, thickeners (such as sodium carboxymethyl cellulose), and the like.

[0097] In some embodiments, the type of solvent in the electrolyte is not particularly limited and can be selected according to actual needs. Specifically, the solvent can be an organic solvent, which can include one or more of other types of chain carbonates, cyclic carbonates, and carboxylic esters. The types of chain carbonates, cyclic carbonates, and carboxylic esters are not particularly limited and can be selected according to actual needs. The organic solvent can also include one or more of diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, vinyl carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, methyl formate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, methyl propionate, and tetrahydrofuran.

[0098] In some embodiments, the electrolyte can also optionally include other additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives capable of improving certain properties of the battery, such as additives capable of improving overcharge performance of the battery, additives capable of improving high-temperature or low-temperature performance of the battery, and the like.

[0099] In an embodiment, the separator film in the battery can employ materials commonly known in the art for battery separator films. As an example, the separator film base film can include one or more of a polyethylene film, a polypropylene film, and a polyvinylidene fluoride film.

[0100] In a second aspect, the embodiments of the present application provide a preparation method of a metal battery cell. The preparation method of the embodiments of the present application includes:

[0101] S01: preparing a polymer slurry;

[0102] S02: printing the polymer slurry on at least one surface of the negative current collector using a 3D printing process to form a polymer layer with a hollow structure, to obtain a negative electrode tab;

[0103] S03: assembling the negative electrode tab, a positive electrode tab, and a separator film into an electrode assembly, and then injecting an electrolyte to form a gel polymer layer from the polymer layer, to obtain a metal battery cell.

[0104] The gel polymer layer on the surface of the negative current collector is printed by a 3D printing process and is in contact with the injected electrolyte. 3D printing (3DP) is also known as additive manufacturing technology (AM), which is a technology for manufacturing solid parts by layer-by-layer material accumulation according to three-dimensional CAD data. The embodiments of the present application can design a three-dimensional model of the gel polymer layer with different shapes (for example, a hollow structure formed by multiple polymer-free material regions) in advance based on computer-aided modeling software, and then quickly and conveniently print the polymer slurry to form a polymer layer with various shapes of hollow structures, which is assembled into an electrode assembly and then in contact with the injected electrolyte to form a gel polymer layer. For example, a UV printer (Ultraviolet LED Inkjet Printer) can be used for printing.

[0105] By using 3D printing technology, the gel polymer layer with a hollow structure on the negative current collector is formed by accurately controlling the morphology and spacing of the printing material. In the prepared metal battery cell, the gel polymer layer with a hollow structure has good wettability for the electrolyte, and after the gel polymer and the electrolyte are in contact, the electrolyte can be locked well, so that the battery has good initial efficiency performance, and the electrolyte is not easy to separate during storage. At the same time, the spatial structure of the multiple polymer-free material regions of the gel polymer layer can reserve a certain space, which is beneficial to alleviate the risk of the negative electrode sheet surface dendrite growth piercing the separator during the cycle process, thereby improving the safety performance of the battery.

[0106] In some embodiments, the hollow structure of the printed polymer layer includes at least one of a network structure, a linear structure, and an island structure.

[0107] In this way, the gel polymer layer of the negative electrode sheet can form at least one structure with a network structure, a linear structure, and an island structure in contact with the injected electrolyte. For example, the gel polymer layer is formed in the negative electrode sheet, and the gel polymer in the gel polymer layer forms multiple strips, and the strips are longitudinally and transversely staggered to form a network structure gel polymer layer with a network of holes; or the gel polymer in the gel polymer layer forms multiple strips, and the strips are parallel to each other to form a linear gel polymer layer with multiple parallel lines, and the layout of the multiple strips is not particularly limited and can be along the length direction or the width direction of the negative electrode sheet, etc.; or the gel polymer in the gel polymer layer forms multiple identical or different island shapes in the negative electrode sheet, and there is no contact between them. The above shapes can be obtained by designing various three-dimensional models of the gel polymer layer in advance based on computer-aided modeling software.

[0108] By printing different shapes of gel polymer layers, not only a certain buffer space is provided for metal deposition on the surface of the negative electrode sheet to better reduce the risk of dendrite piercing the separator, but also the gel polymer layer combined on the surface of the negative electrode current collector can improve the flexibility of the negative electrode sheet as a whole, which is more conducive to the assembly of the battery.

[0109] In some embodiments, the polymer slurry comprises a polymer, a polymerizable monomer, and a photoinitiator, and the polymerizable monomer is a monomer corresponding to the polymer. For example, the polymer comprises a polymethyl methacrylate-based polymer, and the corresponding polymerization unit is methyl methacrylate; the polymer comprises a polyethylene oxide-based polymer, and the corresponding polymerizable monomer can be ethylene oxide; the polymer comprises a polyacrylonitrile-based polymer, and the corresponding polymerizable monomer can be acrylonitrile; the polymer comprises a polyvinylidene fluoride-based polymer, and the corresponding polymerizable monomer can be vinylidene fluoride. In the polymer slurry, the polymerizable monomer and the photoinitiator are added to the polymer, so that part of the polymer can be synthesized in situ during the printing process, further improving the overall uniformity and structure controllability of the polymer layer.

[0110] In some embodiments, the polymer comprises at least one of a polymethyl methacrylate-based polymer, a polyethylene oxide-based polymer, a polyacrylonitrile-based polymer, and a polyvinylidene fluoride-based polymer. The gel polymer layer formed by the above-mentioned types of polymers further improves the safety performance of the battery on the basis of the primary effect performance.

[0111] In some embodiments, the mass ratio of the polymer to the polymerizable monomer is (4:6) to (2:8); for example, the mass ratio of the polymer to the polymerizable monomer is 4:6, 3:7, 2:8, etc.; the polymer slurry with the mass ratio can well form a polymer layer in situ.

[0112] In some embodiments, the photoinitiator accounts for 4-8% of the total mass of the polymer and the polymerizable monomer. The photoinitiator with the above-mentioned mass ratio can well initiate the in-situ formation of the polymer layer by the polymer slurry.

[0113] In some embodiments, the viscosity of the polymer slurry at 25°C is 1500-2000 cps. The polymer slurry with the above-mentioned viscosity is not easy to block, improving the printing efficiency. For example, a certain proportion of polymer and polymerizable monomer are mixed, stirred constantly (the stirring speed is set to 400-700 r / min) to be uniform, and then mixed with a photoinitiator (the mass ratio is 4-8%) to obtain a 3D printing polymer slurry. The prepared polymer slurry has a viscosity of 1500-2000 CPS at 25°C.

[0114] In some embodiments, the temperature condition for printing the polymer slurry is 60-80°C. At this temperature, the polymer slurry can well form a polymer layer.

[0115] In some embodiments, the conditions of the 3D printing process are as follows: the printing speed is 150-200 mm / min; the light wavelength is 360-370 nm; the light intensity is 200-240 mW / cm 2 ; and the light time is set to 60-100 s. The above printing process parameters can make the polymer slurry form a polymer layer well.

[0116] For example, by setting the above printing process parameters in the 3D printing equipment, drawing a 3D printing required area on the operating system, and rapidly spraying the prepared polymer slurry from the nozzle to the surface of the negative current collector, the electrode sheet is transferred to the light curing area, and the 3D printed gel polymer slurry is cured under the above parameter conditions to prepare a 3D printed polymer layer. After subsequent assembly into an electrode assembly, it is in contact with the injected electrolyte to form a gel polymer layer.

[0117]

Battery device

[0118] In a third aspect, the embodiments of the present application provide a battery device. The battery device of the embodiments of the present application comprises the metal battery monomer provided in the first aspect of the embodiments of the present application or the metal battery monomer prepared by the preparation method provided in the second aspect of the embodiments of the present application. The battery device adopts the metal battery monomer provided in the embodiments of the present application, and such a power device has good charge and discharge performance and safety performance, and can work better.

[0119] The battery device provided in the embodiments of the present application can be any one of a secondary battery device, a battery monomer, a battery module, and a battery pack. The battery monomer refers to the metal battery monomer prepared by the preparation method provided in the first aspect of the embodiments of the present application or the metal battery monomer provided in the second aspect of the embodiments of the present application, and comprises a battery shell and an electric core encapsulated in the battery shell. The shape of the battery monomer is not particularly limited, and it can be cylindrical, square or any other shape. As shown in FIG. 1, the battery monomer 10 has a square structure.

[0120] In some embodiments, as shown in FIG. 2, the outer package of the battery monomer 10 can comprise a shell 11 and a top cover assembly 12. The shell 11 can comprise a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a containing cavity. The shell 11 has an opening communicating with the containing cavity, and the top cover assembly 12 is used to cover the opening to close the containing cavity. The positive electrode sheet, the isolation film and the negative electrode sheet contained in the secondary battery of the embodiments of the present application can form an electrode assembly 13 through a winding process and / or a lamination process. The electrode assembly 13 is encapsulated in the containing cavity. The electrolyte is impregnated in the electrode assembly 13. The number of the electrode assembly 13 contained in the battery monomer 10 can be one or more, which can be adjusted according to actual needs.

[0121] The preparation method of the battery cell 10 is known. In some embodiments, the positive electrode sheet, the separator and the negative electrode sheet and the electrolyte can be assembled to form the battery cell 10. As an example, the positive electrode sheet, the separator and the negative electrode sheet can be formed into an electrode assembly 13 through a winding process or a stacking process, the electrode assembly 13 is placed in an outer package, the electrolyte is injected after drying, and the battery cell 10 is obtained through processes such as vacuum packaging, standing, formation and shaping.

[0122] The battery module refers to being assembled by the battery cell 10, that is, can contain a plurality of the battery cell 10, and the specific number can be adjusted according to the application and capacity of the battery module.

[0123] In some embodiments, FIG. 3 is a schematic diagram of the battery module 20 as an example. As shown in FIG. 3, in the battery module 20, a plurality of battery cells 10 can be arranged in sequence along the length direction of the battery module 20. Of course, it can also be arranged in other arbitrary ways. Further, the plurality of battery cells 10 can be fixed by fasteners.

[0124] Optionally, the battery module 20 can also include a housing having an accommodation space, and the plurality of battery cells 10 are accommodated in the accommodation space.

[0125] The battery pack refers to being assembled by the battery cell 10, that is, can contain a plurality of battery cells 10, wherein the plurality of battery cells 10 can be assembled into the battery module 20. The specific number of battery cells 10 or battery modules 20 contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0126] As an example, FIGS. 4 and 5 are schematic diagrams of the battery pack 30. In the battery pack 30, a battery box and a plurality of battery modules 20 arranged in the battery box can be included. The battery box includes an upper box body 31 and a lower box body 32, the upper box body 31 is used to cover the lower box body 32, and forms a closed space for accommodating the battery module 20. The plurality of battery modules 20 can be arranged in the battery box in any manner.

[0127]

Electric device

[0128] In a fourth aspect, the embodiments of the present application also provide an electric device. The electric device of the embodiments of the present application includes the metal battery cell provided in the first aspect of the embodiments of the present application, the metal battery cell prepared by the preparation method provided in the second aspect of the embodiments of the present application, or the battery device provided in the third aspect of the embodiments of the present application. The electric device adopts the metal battery cell or the battery device provided in the embodiments of the present application, and the service life of the electric device is long, and the electric device can work better.

[0129] The power consuming device can be, but is not limited to, a mobile device (e.g., a cell phone, a laptop, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc. The power consuming device can select a secondary battery cell, a battery module, or a battery pack according to its use requirement.

[0130] FIG. 6 is a schematic diagram of a power consuming device as an example. The power consuming device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the requirement of the power consuming device for high power and high energy density, a battery pack or a battery module can be used.

[0131] The power consuming device as another example can be a cell phone, a tablet, a laptop, etc. The power consuming device usually requires thin and light, and a secondary battery can be used as a power source.

[0132] Embodiments

[0133] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are intended to explain the present application only, and are not to be understood as limiting the present application. In the embodiments, specific techniques or conditions not mentioned are performed according to the techniques or conditions described in the literature in the art or according to the product manual. The reagents or instruments not mentioned by the manufacturer are all conventional products that can be obtained commercially.

[0134] Embodiment 1

[0135] Sodium metal battery cell and preparation thereof

[0136] 1.1 The sodium metal battery comprises:

[0137] A positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. The positive active material in the positive electrode sheet is sodium iron pyrophosphate. The negative electrode sheet comprises a copper foil and a conductive carbon layer and a gel polymer layer with a hollow structure arranged on the surface of the copper foil in sequence. The gel polymer layer with a hollow structure is formed by 3D printing into a mesh structure formed by longitudinal and transverse intersecting lines (see FIG. 7), and the polymer material is polymethyl methacrylate (PMMA).

[0138] 1.2 The preparation method of the sodium metal battery comprises:

[0139] (1) Preparation of the positive electrode sheet:

[0140] The positive active material sodium pyrophosphate iron, conductive agent carbon nanotube, binder partial hexafluorophosphoric acid are mixed in N-methyl pyrrolidone (NMP) in a mass ratio of 95:2:3, and stirred sufficiently to form a uniform positive electrode slurry; the positive electrode slurry is coated on the surface of the positive electrode current collector aluminum foil, and after drying, cold pressing, and die cutting, a positive electrode tab with a thickness of 200 μm is obtained, wherein the coating weight of the positive electrode film layer of the positive electrode tab is 200 mg / 1540 mm 2 .

[0141] (2) Preparation of negative electrode tab:

[0142] After coating a layer of 10 μm conductive carbon layer on the surface of the negative electrode current collector copper foil, a polymer layer is printed on the conductive carbon layer, and the steps are as follows:

[0143] 3D slurry preparation: methyl methacrylate (MMA) and polymethyl methacrylate (PMMA) are mixed in a mass ratio of 7:3, heated to 60°C, and stirred (speed set to 400-700 r / min) until PMMA is completely dissolved in MMA, then mixed uniformly with the photoinitiator TPO (the mass concentration of the photoinitiator in the former mixture is 5%), to prepare a 3D printing polymer slurry with a viscosity of 1500-2000 CPS at 25°C.

[0144] 3D printing steps:

[0145] a. Place the 3D printing polymer slurry in the material tank of the 3D printing equipment, and control the temperature at 60°C.

[0146] b. Set the wavelength of the light of the 3D printing equipment to 365 nm, and the light intensity to 220 mW / cm 2 . Set the light curing time to 60 s, the single-layer printing height to 120 μm, the mesh printing line spacing to 1 mm, and the printing speed to 200 mm / min.

[0147] c. Cut the negative electrode current collector copper foil coated with a conductive carbon layer to a fixed size of 300*107 mm, and fix it on the 3D printing fixed platform using wrinkled glue.

[0148] d. Draw the required area of 3D printing on the operating system of the 3D printing equipment, and start the printing operation: quickly spray the prepared polymer slurry from the nozzle onto the surface of the conductive coating of the negative electrode current collector, then transfer it to the light curing area, and cure it under the above wavelength to prepare a 3D printed polymer layer. After single-sided 3D printing is completed, repeat the operation to print the back side.

[0149] (3) Isolation film: commercial PE coated separator.

[0150] (4) Electrolyte:

[0151] In an argon-filled glove box with water content < 1 ppm, diethylene glycol dimethyl ether and tetrahydrofuran were mixed in a mass ratio of 1:3, sodium hexafluorophosphate (NaPF6) was added, and after stirring uniformly, an electrolyte with a sodium hexafluorophosphate concentration of 1.0 mol / L was obtained.

[0152] (5) Assembly:

[0153] The positive electrode sheet, the separator film, and the negative electrode sheet prepared in the above steps were stacked in order, so that the separator film was between the positive electrode sheet and the negative electrode sheet, and then the stacked components were wound to obtain an electrode assembly; the electrode assembly was arranged in a shell, and after drying, an electrolyte was injected, so that the 3D printed polymer layer formed a gel polymer layer; after processes such as formation and standing, a sodium metal battery monomer was obtained.

[0154] Examples 2-8

[0155] Difference from Example 1: See Table 2 for details.

[0156] Comparative Example 1

[0157] The difference between this comparative example and Example 1 is that the negative current collector surface is not printed with a polymer.

[0158] Comparative Example 2

[0159] The difference between this comparative example and Example 1 is that the negative current collector surface is directly coated with a polymer to form a polymer layer (without a reticular hollow structure).

[0160] Performance test

[0161] 1. Initial efficiency test

[0162] The sodium metal battery monomer was charged at 0.33C rate to a voltage equal to 3.65V at 25°C normal temperature, and the first charge capacity C1 was tested, and then discharged at 0.33C rate to a voltage equal to 1.5V, and the first discharge reversible capacity D1 was measured, and the ratio of D1 / C1 was the initial efficiency of the battery.

[0163] 2. Cycle performance test

[0164] The sodium metal battery monomer was charged at 0.33C rate to a voltage equal to 3.65V at 25°C normal temperature, and then discharged at 0.33C rate to a voltage equal to 1.5V, and the reversible capacity C0 was measured. The charging and discharging was repeatedly until the discharge capacity Cn / C0 of a certain cycle was ≤80%, and the total cycle number was recorded as X-Cycle. Among them, Cn was the reversible capacity at the nth cycle.

[0165] 3. Storage performance test

[0166] The metal battery monomer is charged at 0.33C rate to a voltage equal to 3.65V at room temperature of 25°C, and then discharged at 0.33C rate to a voltage equal to 1.5V, and the reversible capacity is measured as C0, then the battery monomer is stored in an environment at 25°C, and every 30 days, it is charged at 0.33C rate to a voltage equal to 3.65V, and then discharged at 0.33C rate to a voltage equal to 1.5V, and the reversible capacity is measured as Cn, and then Cn / C0 is obtained to obtain the storage life attenuation rate of the battery monomer, and the storage and repeated charging and discharging are continuously performed until the discharge capacity Cn / C0 of a certain cycle is less than or equal to 80%, and the storage days Dn of the battery are recorded.

[0167] The test results are as follows:

[0168] (1) The initial efficiency of different electrolyte injection coefficients

[0169] Table 1 shows the initial efficiency of different electrolyte injection coefficients in Example 1, and the electrolyte injection coefficient is the mass of electrolyte injected into the battery monomer / the capacity of the battery monomer=g / Ah; it can be seen from the data in Table 1 that the initial efficiency is continuously improved with the increase of the electrolyte injection amount.

[0170] Table 1

[0171] (2) The test results of each example with an injection coefficient of 5.5g / Ah are shown in Table 2.

[0172] Table 2

[0173] The area ratio refers to the percentage of the contact area between the gel polymer and the conductive carbon layer to the total area of the printed area of the gel polymer layer.

[0174] The data in Table 2 shows that:

[0175] Comparative Example 1 does not print a gel polymer layer on the metal battery monomer, and the entire negative electrode sheet has low liquid locking capacity, resulting in liquid deficiency. In addition, there are few ion channels between the negative electrode and the positive electrode, and sodium dendrites are more likely to grow. The 25°C cycle life test result is that the cycle life is only about 300Cls, and after 300cls, the battery top appears negative electrode sheet delamination due to electrolyte deficiency. In addition, the 25°C storage time of Comparative Example 1 is 180Days. Comparative Example 2 coats a whole layer of gel polymer layer without a three-dimensional hollow structure, and the cycle number and storage time of the metal battery monomer are limitedly improved. However, the gel polymer layer with the special structure in the application significantly improves the cycle number and storage time.

[0176] The above only describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A metal battery cell, characterized by, The metal battery cell comprises a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte solution; wherein the negative electrode sheet comprises a negative electrode current collector and a gel polymer layer stacked with at least one surface of the negative electrode current collector, and the gel polymer layer has a hollow structure.

2. The metal battery cell of claim 1, wherein, The hollow structure of the gel polymer layer comprises at least one of a network structure, a linear structure and an island structure.

3. The metal battery cell of claim 2, wherein, The gel polymer layer has a network structure, and the size of the network holes in the network structure is 1-10 mm; or The gel polymer layer has a linear structure, and the distance between adjacent lines in the linear structure is 1-10 mm.

4. The metal battery cell of any one of claims 1-3, wherein, The thickness of the gel polymer layer is 5-150 μm; And / or, the percentage of the gel polymer area on the surface of the negative electrode current collector to the total area of the gel polymer layer is 5-40%.

5. The metal battery cell of any one of claims 1-4, wherein, The gel polymer comprises at least one of a polymethyl methacrylate-based gel polymer, a polyethylene oxide-based gel polymer, a polyacrylonitrile-based gel polymer and a polyvinylidene fluoride-based gel polymer.

6. The metal battery cell of any one of claims 1-5, wherein, The negative electrode current collector and the gel polymer layer are provided with a conductive coating.

7. The metal battery cell of claim 6, wherein the metal battery cell is a lithium battery cell. The conductive coating comprises a conductive carbon layer; and / or The thickness of the conductive coating is 2-20 μm.

8. A method of producing a metal battery cell, characterized by, The method comprises: preparing a polymer slurry; printing the polymer slurry on at least one surface of a negative electrode current collector by a 3D printing process to form a polymer layer with a hollow structure, thereby obtaining a negative electrode sheet; assembling the negative electrode sheet, a positive electrode sheet and a separator into an electrode assembly, and then injecting an electrolyte solution to form a gel polymer layer from the polymer layer, thereby obtaining a metal battery cell.

9. The production method according to claim 8, wherein The hollow structure of the polymer layer comprises at least one of a network structure, a linear structure and an island structure.

10. The production method according to claim 8 or 9, characterized by, The polymer slurry comprises a polymer, a polymerized monomer and a photoinitiator, and the polymerized monomer is a monomer corresponding to the polymer.

11. The production method according to claim 10, wherein The polymer comprises at least one of a polymethyl methacrylate-based polymer, a polyethylene oxide-based polymer, a polyacrylonitrile-based polymer and a polyvinylidene fluoride-based polymer.

12. The production method according to claim 10 or 11, characterized by, The mass ratio of the polymer to the polymerized monomer is (4:6)-(2:8); And / or, the photoinitiator accounts for 4-8% of the total mass of the polymer and the polymerized monomer.

13. The production method according to any one of claims 8 to 12, wherein The viscosity of the polymer slurry at 25°C is 1500-2000 cps; The temperature condition for printing the polymer slurry is 60-80°C.

14. The production method according to any one of claims 8 to 13, wherein The conditions of the 3D printing process comprise: (1) the printing speed is 150-200 mm / min; (2) the light wavelength is 360-370 nm; (3) light intensity is 200-240 mW / cm 2 ; (4) the light exposure time is set to 60-100 s.

15. A battery device characterized by comprising: The metal battery cell comprises a metal battery cell prepared by the method of any one of claims 8-14.

16. An electrical device, comprising: The battery device comprises the metal battery cell of any one of claims 1-7, the metal battery cell prepared by the method of any one of claims 8-14 or the battery device of claim 15.

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